This invention relates in general to an apparatus and method for making a reclosable package and, more particularly, to an apparatus and method for applying a reclosable fastener to a package for containing food products.
Packages formed from thin flexible thermoplastic materials are increasingly used for packaging food items such as sliced luncheon meats as well as a wide assortment of other products. The food item is hermetically sealed within the package to maintain the desired freshness prior to usage by the consumer. Often only a portion of the contents are utilized when the package is opened. To retain the freshness of the remaining contents of the package, a reclosable fastener is often incorporated with the package to allow the package to be reclosed after opening.
Reclosable fasteners of the type mentioned are typically formed from a strip of separable flexible material having male and female interlocks carried on opposed facing surfaces of the material. The fastener strip is sealed to the inner surfaces of the formed and covering web material which encloses the product. The fastener strip is positioned near an edge of the package to allow removal of the product or a portion thereof through the opening formed by separation of the strip. The package may then be reclosed by interlocking the fastener strip to retain the freshness and quality of the product remaining in the package.
During manufacture of the reclosable packages of this type, it is critical that the fastener strip be placed in the desired alignment with the formed and closure webs to ensure proper sealing of the package. The continuous fastener strip is typically maintained on a supply roll and brought into position between the formed and closure webs by a series of guide rollers. Improper positioning of the fastener strip has been a significant problem which results in improperly formed packages and costly manufacturing delays. Even when placed under tension, the flexible fastener strip periodically slips off of the guide rollers and must be manually repositioned. Increasing the tension applied to the fastening strip is an unsatisfactory remedy for this problem as the strip returns to its unstretched condition after the package has been formed and causes distortion of the package. The ability to manufacture reclosable packages at commercially acceptable rates has thus proven to be difficult because of the problems encountered in properly aligning the fastening strip.